World record 800m runner David Rudisha said he’s considering taking part in the 4x400m relay at the World Athletic Championships in Moscow this summer, and is daring Jamaican sprinter Usain Bolt line up against him on the track.

Rudisha has always been willing to face Bolt, his close friend, in a relay or a 400m exhibition race or a dark gym, like in Rocky III, and thinks he has a 50/50 shot against the world’s fastest man.

“[Bolt] is quick in 100 and 200 meters and is really unmatchable,” Rudisha said back in September. “But over the distance I hold the edge. If I prepare for more speed, who knows? I may be capable of beating him.”

To further up the ante, Rudisha broke his own personal best at home in Kenya Friday, running a 45.15 seconds to win his heat at the AK/NBK National Track and Field Series meet in Nairobi. Your move, Bolt.